To my knowledge, chests do not reappear in the exact same spot. Plus, respawn rates changed drastically for chests in the old world when they were changed to drop mostly rares instead of uncommons when Cataclysm hit.
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user2974Jul 16 '11 at 19:17

I am reinforcing Powerlord's knowledge that chests do not reappear in the same spot. As far as I know, chests have a variable respawn rate to begin with.
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Raven Dreamer♦Jul 16 '11 at 20:12

1 Answer
1

You are not supposed to camp chests..
The chests in the game (Solid Chest etc) are still in the old world and contain mostly very low-level loot that won't do you any good.
In the higher level areas there are no chests at all, so don't waste time with chests.

Also they don't respawn at the exact same spot. There are a number of spots where they can spawn but it's rather unlikely they will re-appear at the same one.